The Determination of Metronidazole and Chlorhexidine Gluconate in Metronidazole and Chlorhexidine Lotion by HPLC

Objective “To establish an HPLC method for the determination of metronidazole and chlorhexidine gluconate in metronidazole and chlorhexidine lotion. Method Using Agilent Eclipse-XDB-C18 chromatographic column, with 0.05 mol·L-1 potassium dihydrogen phosphate solution 1000 ml plus 13.2 ml 10% tetrabutylammonium hydroxide aqueous solution (pH adjusted to 3.5 by phosphoric acid)-acetonitrile (77:23) as Mobile phase, detection wavelength 230 nm. Results The two components could be separated well. The linear ranges of metronidazole and chlorhexidine acetate were 36.33~59.04 μg·ml-1 (r = 0.9994) and 35.45~220.11 μg·ml-1 (r = 1).); The average recoveries were 100.6% and 100.5 %, and the RSD were 0.42% and 0.58%. Conclusion: The method is simple and specific, and the result is more accurate and reliable. Which is suitable for simultaneous determination of two components in compound preparations.

Development of a high-performance liquid chromatography method for simultaneously analyzing Guanosine 5’-monophosphate (GMP) and Inosine 5’-monophosphate (IMP) in food

This study aimed to develop a HPLC method to simultaneously analyze guanosine 5’-monophosphat (GMP) and inosine 5’-monophosphat (IMP) in food products. Sample preparation procedure was simple, fast. A C18 column (250 mm × 4.6 mm, 5 µm) was used as stationary phase, and a mixture of 10 mM potassium dihydrogen phosphate and 5 mM sodium heptanesulfonate was applied as mobile phase, and PDA detector at 250 nm. The method validation followed AOAC criteria. Selectivity, linearity (R2 > 0.999), recovery (IMP: 90.5 % - 102.8 %, GMP: 91.5 % - 103.9 %), repeatability (RSDR of IMP: 3.07 % and GMP: 2.83 %) were acceptable to determination GMP and IMP in food matrix under AOAC guidelines. LOD of GMP and IMP were of 2.32 and 2.77 mg/kg, respectively. This method was used to determination GMP, IMP in food products collected in Hanoi markets.

Freestanding Flexible Sensor Based on 3ω Technique for Anisotropic Thermal Conductivity Measurement of Potassium Dihydrogen Phosphate Crystal

A new freestanding sensor-based 3ω technique is presented here, which remarkably expands the application of traditional 3ω technology to anisotropic materials. The freestanding flexible sensor was fabricated using the mature flexible printed circuit production technique, which is non-destructive to the samples and applicable to porous surfaces. The thermal conductivities of potassium dihydrogen phosphate (KDP) crystal along the (100), (010) and (001) crystallographic planes were measured based on this new sensor at room temperature. We found that the freestanding flexible sensor has considerable application value for thermal properties’ characterization for crystals with anisotropic thermophysical properties and other structures for which the traditional 3ω technique is not applicable.

New stability indicating RP-HPLC-PDA method for determination of mifepristone in bulk and tablet formulation

Background Mifepristone is progestational and glucocorticoid hormone antagonist. The objective of this study is to develop simple and economical stability indicating RP-HPLC method for the determination of mifepristone in bulk and tablet formulation. Result The chromatographic separation was achieved on Qualisil BDS C8 column with mobile phase containing of mixture of Buffer (Potassium dihydrogen ortho phosphate, pH to 3.0 with ortho phosphoric acid) and Organic Solvent (Acetonitrile) 60:40 v/v pumped at flow rate 0.6 mL min−1. The detection of elute was performed using PDA detector at 305 nm. Mifepristone was eluted at 8.67 min. According to international conference on harmonization Q2(R1) guideline, method was validated and shows satisfactory results for accuracy, precision, linearity, ruggedness, robustness, detection limit, quantitation limit. The method indicated to be linear in the series of concentration 3–18 µg mL−1, and correlation coefficient was 0.9997. In acidic, basic, oxidative, thermal, photolytic forced degradation conditions, the peak of degradation product was clearly and well separated from drug peak without any interference in quantitative analysis. This represents stability indicating nature of established method. Conclusion The established RP-HPLC method is simple, accurate, specific, precise, robust, rugged, sensitive, and economical in nature which can be utilized for routine analysis of mifepristone in bulk and pharmaceutical formulation.